C. D. Kacher

Gas phase chromatography of halides of elements 104 and 105

On-line isothermal gas phase chromatography was used to study halides of261104 (T1/2=65 s) and262,263105 (T1/2=34 s and 27 s) produced an atom-at-a time via the reactions248Cm(18O, 5n) and249Bk(18O, 5n, 4n), respectively. Using HBr and HCl gas as halogenating agents, we were able to produce volatile bromides and chlorides of the above mentioned elements and study their behavior compared to their lighter homologs in Groups 4 or 5 of the periodic table. Element 104 formed more volatile bromide than its homolog Hf. In contrast, element 105 bromides were found to be less volatile than the bromides of the group 5 elements Nb and Ta. Both 104 and Hf chlorides were observed to be more volatile than their respective bromides.

Solution Chemistry of Element 104: Part I. Liquid-Liquid Extractions with Triisooctylamine

Liquid-liquid extractions of element 104 (Rf), Zr, Nb, Th, and Eu were conducted using triisooctylamine (ΠΟΑ), an organic soluble high molecular weight amine. Initial studies were conducted studying the extraction of Zr, Nb, Th and Eu from 12 M HCl in an organic phase of TIOA in benzene. Tracer loss due to thin sample formation was examined using Zr. Based on the tracer extraction results, Rf extractions were conducted with an aqueous phase of 12 M HCl and an organic phase of 1.0 M and 0.1 M TIOA in benzene. The Rf extraction results showed that 0.1 M TIOA in benzene extracts Rf to a greater extent than 1.0 M TIOA in benzene. This difference is attributed to Rf loss during thin sample formation. The extraction of Rf by ΤΊΟΑ is further evidence that Rf behaves similar to the group 4 elements.

Solution Chemistry of Element 104: Part II. Liquid-Liquid Extractions with Tributylphosphate

Liquid-liquid extractions of element 104 (Rf), Zr, Nb, Hf, Th, and Pu(IV) were conducted using tributylphosphate (TBP) in benzene. Initial studies were conducted using Zr and Nb. The effect of TBP, HCl, chloride, and hydrogen ion concentrations on Zr and Nb extraction was examined. Based on the results from these experiments, it was decided to examine Rf extraction into 0.25 M TBP in benzene as a function of HCl, chloride, and hydrogen ion concentrations between 8 and 12 M. Studies of these extraction conditions were carried out using Zr, Hf, Th, Pu, and Rf. The 65-second Rf was produced via the Cm(0,5n) reaction at the 88-Inch Cyclotron at Lawrence Berkeley Laboratory. The results show that extraction for these elements increases or remains high as a function of HCl concentration. However, in the experiments in which the chloride and hydrogen ion were varied, Rf extraction differed from that of the group 4 elements and behaved more like Pu(IV).

Chemical Studies of Rutherfordium (Element 104) : Part II. Solvent Extraction into Tributylphosphate from HBr Solutions

The chemical properties of element 104, rutherfordium (Rf), and its group 4 homologs and other tetravalent cations were studied by solvent extraction into tributylphosphate (TBP) from various concentrations of HBr and HCl. Since bromide is a larger and softer (more polarizable) anion than chloride, the stability of Rfbromide complexes was expected to differ from the stability of Rf-chloride complexes, and a comparison of the two systems was undertaken. Our studies showed that the extraction trend decreased in the order Zr > Hf > Rf/Ti for HBr, compared to Zr > Hf > Rf > Ti for HCl, showing that Rf and Ti did not extract as well in either system, probably because they hydrolyzed more easily than Zr and Hf.

Chemical Studies of Rutherfordium (Element 104) : Part III. Solvent Extraction into Triisooctylamine from HF Solutions

The extraction of element 104, rutherfordium (Rf), and its group 4 homologs into 0.25 M triisooctylamine (TIOA) in o,m,p-xylene from various concentrations of hydrofluoric acid was studied. This extraction system was of particular interest because all group 4 cations studied formed complexes with the same coordination number (CN) of 6. Therefore, species extracted were similar and the extractability depends on the radii of the fluoride complexes. The studies showed that the extractability for the group 4 elements in this system decreases in the order Ti > Zr ~ Hf > Rf, in inverse order from the decrease in ionic radii Rf > Zr ~ Hf > Ti. This order is different than the order in the hydrolysis, TBP-HC1, and TBP-HBr extraction systems where Rf, due to decreasing CN, behaves more similarly to Ti than to Zr and Hf.